1. Field of the Invention
The present invention relates to a lifter device for a vehicle seat.
2. Description of the Related Art
A lifter device for a vehicle seat is designed such that it has front and rear links each coupling a frame of a seat cushion and a floor member (a floor panel or an upper channel mounted to the floor panel), and lifts and lowers the seat cushion according to a swing movement of the front and rear links (see, for example, JPU 56-105449A). This makes it possible to adjust a height position of a seating surface of the seat cushion.
Meanwhile, in the event of a frontal collision of a vehicle, a frontward displacement force will occur in the seat cushion by collision energy, whereas, in the event of a rear collision of the vehicle, a rearward displacement force will occur in the seat cushion by collision energy.
In the event of the collision, if the seat cushion is in a lifted position, a deformation (buckling) of the link become larger, because the link is raised more uprightly than when the seat cushion is in a lowered position, so that an amount (distance) of frontward or rearward displacement of the seat cushion becomes larger. This results in an increase in amount (distance) of displacement of an occupant seated on the seat cushion, and an increase in acceleration to be applied to the occupant.